This is a note to let you know that I've just added the patch titled mailbox: zynq-ipi: fix error handling while device_register() fails to the 5.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: mailbox-zynq-ipi-fix-error-handling-while-device_reg.patch and it can be found in the queue-5.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 412f87347b5a78aaba086672764d1c2d833ce4fc Author: Yang Yingliang <yangyingliang@xxxxxxxxxx> Date: Thu Nov 10 23:08:22 2022 +0800 mailbox: zynq-ipi: fix error handling while device_register() fails [ Upstream commit a6792a0cdef0b1c2d77920246283a72537e60e94 ] If device_register() fails, it has two issues: 1. The name allocated by dev_set_name() is leaked. 2. The parent of device is not NULL, device_unregister() is called in zynqmp_ipi_free_mboxes(), it will lead a kernel crash because of removing not added device. Call put_device() to give up the reference, so the name is freed in kobject_cleanup(). Add device registered check in zynqmp_ipi_free_mboxes() to avoid null-ptr-deref. Fixes: 4981b82ba2ff ("mailbox: ZynqMP IPI mailbox controller") Signed-off-by: Yang Yingliang <yangyingliang@xxxxxxxxxx> Signed-off-by: Jassi Brar <jaswinder.singh@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/mailbox/zynqmp-ipi-mailbox.c b/drivers/mailbox/zynqmp-ipi-mailbox.c index f9cc674ba9b7..1d0b8abbafc3 100644 --- a/drivers/mailbox/zynqmp-ipi-mailbox.c +++ b/drivers/mailbox/zynqmp-ipi-mailbox.c @@ -493,6 +493,7 @@ static int zynqmp_ipi_mbox_probe(struct zynqmp_ipi_mbox *ipi_mbox, ret = device_register(&ipi_mbox->dev); if (ret) { dev_err(dev, "Failed to register ipi mbox dev.\n"); + put_device(&ipi_mbox->dev); return ret; } mdev = &ipi_mbox->dev; @@ -619,7 +620,8 @@ static void zynqmp_ipi_free_mboxes(struct zynqmp_ipi_pdata *pdata) ipi_mbox = &pdata->ipi_mboxes[i]; if (ipi_mbox->dev.parent) { mbox_controller_unregister(&ipi_mbox->mbox); - device_unregister(&ipi_mbox->dev); + if (device_is_registered(&ipi_mbox->dev)) + device_unregister(&ipi_mbox->dev); } } }